This invention relates to pouch machines and, more particularly, to an improved rotary knife apparatus used in connection with a pouch form, fill and seal machine capable of sequentially discharging pouches into pouch stacks along a product transfer conveyor and dynamically varying the pouch counts in the pouch stacks.
The present application is related to the following United States patent applications filed on even date herewith and entitled: "Convertible Pitch Knife Apparatus", by P. Dieterlen, Ser. No. 08/338,848 (attorney docket No. J&C-139); "Low Thermal Inertia Sealer", by M. Wildmoser, Ser. No. 08/338,870 (attorney docket No. J&C-140); "Convertible Pitch Pouch Machine", by F. Oliverio and B. Makutonin, Ser. No. 08/338,860 (attorney docket No. J&C-142); and "Tuck Roll With Improved Web Tension Control", by M. Wildmoser and Frank G. Oliverio, Ser. No. 08/338,839 (attorney docket No. J&C-147), each of which is expressly incorporated herein by reference.
In pouch machines of the known art, such as disclosed in U.S. Pat. No. 3,597,898 which is herewith incorporated herein by reference, a flat web of heat sealable material is continuously fed from upstream of the pouch machine to be longitudinally folded upon itself by a plow or similar device. In this form, the thus-folded web is fed about a sealer which contacts the folded web along vertical heated land areas to form transverse vertical seals and, thus, a series of open pouches along the web. In this way, the web of open pouches is passed around a filler wheel, filled with product and then sealed along the top edge of the web. The web of filled pouches then passes downstream to a motor-driven rotary knife apparatus which cuts the web along the transverse vertical seals into separate individual pouches and deposits them onto a transfer for subsequent cartoning or other secondary packaging.
In a typical cartoning operation of the known art, conveyors are used to transfer individually cut pouches away from the rotary knife to a cartoner machine. If the pouches are required to be stacked in preselected counts prior to being delivered to the cartoner, additional transfer conveyors and stacking apparatus must be operatively placed between the rotary knife and the cartoner machine to count, stack and move the pouches prior to cartoning.
It will be appreciated that it is desirable to reduce the number of pouch transfer operations occurring between the rotary knife and the cartoner machine. In one respect, reducing the number of pouch transfers makes the overall cartoning operation more reliable. In another, and equally important respect, floor space is saved and economies result by the reduction or elimination of conveyor and stacking apparatus required for the pouch transfer.
Prior to the present invention, it was known to control angular drop-off of pouches from a rotary knife to product transfer conveyors via vacuum and air ports cooperating within the rotary knife apparatus. One such apparatus, disclosed in Hartman et al., U.S. Pat. No. 3,961,697, provides a plurality of vacuum and air ports within the rotary knife apparatus for depositing individually cut pouches in side-by-side shingled fashion onto a moving product transfer conveyor. Further examples are disclosed in Benner, Jr. et al., U.S. Pat. No. 4,872,382, and Scarpa et al., U.S. Pat. No. 5,220,993, wherein a rotary wheel with radially extending suction cups first grasps and then expels cut pouches at predetermined angular drop-off points along the wheel and transversely across a transfer conveyor.
The known rotary knife and transfer apparatus generally have a series of radially extending and circumferentially spaced suction cups for grasping filled pouches cut from a web. As the suction cups move along a circular path about the rotary knife apparatus, vacuum is typically applied from a vacuum chamber to the suction cups along a segment of the circular path to hold the pouches. As the suction cups reach predetermined drop-off points, vacuum is withdrawn and air is blown through the suction cups to expel the pouches at the predetermined drop-off points.
In such rotary knife and transfer apparatus, axial bores are provided in the wheel to communicate with the suction cups. Arcuate negative and positive pressure slots are provided along a fixed shoe which cooperates with the wheel as the wheel rotates. The axial bores of the wheel rotate relative to the fixed arcuate slots in such a way that vacuum and air is alternately applied to the suction cups for holding and expelling the pouches as the axial bores overlie the negative and positive pressure slots in the fixed shoe, respectively.
It will be appreciated that while these advances have proven useful, the present rotary knife apparatus do not readily accommodate the formation of stacks of pouches directly from the knife, and particularly do not provide for forming such stacks in dynamically variable selective pouch counts, i.e., stacks with varied numbers of pouches. Furthermore, the known apparatus does not provide for quick and inexpensive changing of the number of drop-off points along the rotary knife wheel. Rather, the drop-off pattern of the known rotary knife apparatus is typically fixed and, thus, requires a changing of at least the fixed shoe to vary the number of drop-off points. In addition, the drop-off pattern of the known rotary knife apparatus cannot be easily changed to accommodate for different configurations of product transfer conveyors nor, as stated, for variable count stacks.
Accordingly, a primary objective of the present invention has been to provide a dynamically controllable rotary knife apparatus capable of sequentially discharging pouches into pouch stacks along a product transfer conveyor.
Another objective of the present invention has been to provide a rotary knife apparatus capable of dynamically varying pouch counts in the pouch stacks discharged along the product transfer conveyor.
It has been a further objective of the present invention to provide a rotary knife apparatus capable of dynamically changing drop-off patterns of pouches to accommodate for different configurations of product bucket conveyors beneath the apparatus.